Fix Brightness Control Not Working for Ubuntu 14.04 & Linux Mint 17

Two of the most prominent issue with Ubuntu 13.10 are brightness control and sound. We saw how to fix no sound issue in an older post. In this quick post, we’ll see how to fix brightness function key not working in Ubuntu 14.04.

This article was originally written for Ubuntu 13.10 but it is equally able to fix brightness issue in Ubuntu 14.04 as well as Linux Mint 17.

On my Dell Inspiron, using the function key to change the brightness did not yield any results. Brightness was at the maximum and my attempts to lower it went in vain.

It turns out, there are two bugs related to brightness issue in Ubuntu. One relates to Nvidia graphics card and other relates to Intel graphics card. The solution, that worked for me, is for Intel one. Let’s first find out what graphics/video card to do you have.

Find video/graphics card in Ubuntu and Linux Mint

Run the command below in terminal to know what video card is used for the backlight/brightness:

ls /sys/class/backlight/

As you can see, the output for me is dell_backlight and intel_backlight. An indicator that the graphics card in use is Intel. Another way to find out the graphics card would be to go in System Settings->Details->Graphics. You can see the graphic card in use.

About Abhishek Prakash

I am Abhishek Prakash, 'creator' of It's F.O.S.S. Working as a software professional. I am an avid Linux lover and Open Source enthusiast. I use Ubuntu and believe in sharing knowledge. Apart from Linux, I love classic detective mystery. Huge fan of Agatha Christie work.

Unfortunately nothing here worked for me. ls /sys/class/backlight/ produces no output and there is nothing about graphics in my system settings.
sudo touch /usr/share/X11/xorg.conf.d/20-intel.conf also does not produce anything.

Hi! Thanks for your instructions, they are very enlightening! I had tried it on Ubuntu 14 and it worked without problems. It doesnt work on Ubuntu 16, though. Do you have any other solution for this edition?

I haven’t had any problem until I just updated to Linux Mint 17.3 Cinnamon 64-bit. My processor is Intel Core Duo T5800 @ 2.00 GHz x 2 and my graphics card is Intel Mobile 4 Series. I added the 20-intel.conf file, as it was not present, log off and back on, then tried rebooting and the brightness function keys still do not work. If I try to use the Brightness app, it never changes the value from 100% :-(

Hi,
the above method can adjust the brightness now. But after doing those changes, i can’t put my laptop to suspend state. Whenever i click suspend, black screen comes for 5-6 seconds, then again login page appears. Please help with this issue.
Thanks

It does not work for me
I get this in the Terminak – (unity-control-center:12570): screen-cc-panel-WARNING **: Error getting brightness: GDBus.Error:org.gtk.GDBus.UnmappedGError.Quark._gsd_5fpower_5fmanager_5ferror.Code0: Screen backlight not available
any ideas – many thanks

Thank you, Abhishek Prakash. Another super post for those of us who don’t have the depth of experience with FOSS. Think I’d give up without people like you! Initial solution worked perfectly on my Sager (Clevo) SM150P. Followup solution with the sysvinit-backlight cinched it.

My GPU is Nvidia 770M Optimus so the Intel chip has priority. Not sure how it’ll work when I run a 3D game. Haven’t got there yet. I’ll reply when I try that.

After implementing your advice I can adjust the brightness, but every time when I reach the lowest brighness possible – it gets blocked and I cannot return to a higher level of brightness.
Have you encountered a similar problem? My computer is Samsung NP-R509.

Tried following the code in the terminal that you wrote but when I logged out the screen went black and can’t log back again. Went to the technician and the whole OS will be erased and re installed. Thank you :)

Abishek, please delete the quote start (“) before the word section, it has resulted in command prompt boot. Even safe mode gui doesnt work. After deleting that file through safe mode command prompt , GUI worked. Brightness adjustment works if copied without that start quote. I am new to Linux thought that quote to be part of command (it doesn’t have corresponding end quote). Thanks.

Hey ABHISHEK, i tried this on an asus X555LA-EH51 and it did not work, i am currently running ubuntu 15.10, i logged out and no results and then restarted no results. i do notice that the desktop flickers when i hit f2 without using the function key but i cant say whether or not it did this before. a reply would be greatly appreciated because the more i use ubuntu is the more i love it. Thanks.

ARG didn’t work for me. It did something, now when I use the key shortcut to change the brightness the brightness bar appears in the top right hand corner of the screen (which was not the case before) but then when I try to increase or decrease it automatically comes back to the current setting of brightness…

with this things I was then able to successfully change the brightness of the screen
using System Settings > Brightness & Lock in Ubuntu 14.04.
I tried with “ideapad” instead of “intel_backlight” (see step 3.) since at
some moment I saw that the output of the command “ls /sys/class/backlight/” was

ideapad intel_backlight

…and I know that “ideapad” is a word related to the brand of my laptop :-).

But now, when I do the same I obtain as output “acpi_video0 intel_backlight”. I dont know what changed, but the steps I fallowed are the mentioned.

It seem also that the fn hotkeys for adjusting the brightness start to work when my laptop suspends for a while and I start to use it again. Strange.
I hope this helps some one else.

Brilliant! I have 4 old Samsung R530 machines here (for use by a charity) on which I have installed Linux Mint 17.2 Rafaela xfce (replacing Windows 7). Almost everything works much better but the brightness on all of them was stuck and could not be adjusted. The graphics card is Intel and the fix works perfectly. Thank you so much!

I solved the problem very easily and I think it will work with everybody, LOCK linux to starting screen where you have to log on and change brightness, log back in and brightness stays where you like it to STAY.. SHARE THIS INFORMATION at other topics

I did this and after logging out, GUI is not working for me. Its just a blank screen. I tried booting through recovery mode but hell, It is not logging me in(in terminal) even when I am entering the correct log in information. At this stage also if I try to switch to GUI mode(by pressing Ctrl+Alt+F7) it leaves a blank screen. What should I do?

I don’t know any code, i’m completely new to linux. After 2 weeks of trying out all the solutions in found in fora, I found this bypass; Set your resolution with the function button BEFORE Ubuntu starts up :D. I’m quite sorry for not giving a real solution, I’d really like to contribute to free stuff but this is satisfying enough for me, I have to press esc anyway or it won’t boot.

–hai abhishek and
amar prahbu,i really want to install ubuntu on my brother laptop,
before he is running windows 8 ,and all working fine,but when I try
to install ubuntu ,the fn keys doesnt work and I try what amar prabu
said,it just help me little, I can reduce the brightnes using amar
prabu way,but the light still so shine,.

– I want to make the
brightnes working fine as my laptop asus x201e,i can reduce the
brightnes 16 times or level,but on asus x401u ,its just work 2 times
or two level,so the light still very shine.

Hi
Acer 5332 laptop Ubuntu Gnome 14.04.
Creating config file 20-intel.conf as above gave me a blank lit screen on reboot and I could not log in :( I had work out a way to delete the file before I could reboot my system!
This method works however:

Hey, thank you! it worked on my Acer Extensa 2509. Anyway now I have the brightness commands inverted (if I try to increase the brightness, it decrease, and viceversa). Not a big deal, but maybe someone can help me to set it in the right way..?

I solved it. I was able to login to command line (with ctrl+alt+F1), I browsed to the new created file, deleted it and rebooted the system.
I made a mistake copying the code.. made a typo…
thanks,
all the best,
romeo

hi guy.. thanks for the post.
anyway I try with my ubuntu 14.04 but ended up in low/graphic/mode.
tryed to fix USING Recovery Mode through the recovery menu failsafx. With no avail.
Can you give me a tip about how to delete the file I-ve inserted?
it seems either failfax does not work and also I cannot open a terminal from failfax.
thanks,
hard time here .. that-s low/graphic/mode is driving me crazy.. :)

Hi,
Thanks for these tips but alas! none of them worked for me.
I own an ASUS Zenbook UX303LN-R4197H on which only the brightness Fn keys were not working (backlight and sound volume OK) under Linux Mint 17.1 64-bits. This laptop is equipped with 2 graphic cards (Intel HD4400 & Nvidia GeForce GT840).
So for those like me, here’s the tip I found on Linux Mint Forums (http://forums.linuxmint.com/viewtopic.php?f=49&t=180794) that worked:
it consisted in updating the Grub file with this line
GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_osi=”
but not GRUB_CMDLINE_LINUX_DEFAULT=”quiet splash acpi_backlight=vendor”
and uncommenting GRUB_CMDLINE_LINUX=””

Sup people
The edit works great but when you set the brightness control to its lowest the screen literally becomes BLACK(as in the p.c. has shutdown black) .How do you edit it to the pint where the lowest brightness is just bright enough?

I must say thank you. Thank you very much for the information provided. I am a subscriber to your email news letter and I am a fan user of linux (ubuntu, gnome,kde). I wish you the best. Have a pieceful life!

For all of you running a Laptop with NVIDIA Card and who are still not able to get the f* function keys for brightness to work, just follow the steps below. It worked very well for my system (Samsung q45, Intel Dualcore T7100 @ 1,8Ghz , Nvidia Geforce 8400M G 512) running Linux Mint 17.

In command line, type in:

sudo gedit /etc/X11/xorg.conf

You will have to enter your root password.

Now, you should see:

___________________________________________________

Section “Device”

Identifier “Device0”

Driver “nvidia”

VendorName “NVIDIA Corporation”

EndSection

___________________________________________________

If you see nothing, just enter all the lines above and follow up with the next step below

I’ve tried so many solutions out of the net and nothing had helped me until I came to this solution. But be aware that these steps only working for NVIDIA Grafics and you must have chosen the NVIDIA Driver in your system in “Administration -> Driver Manager”.

please tell me how can i blacken the screen with shortcut key. e.g. i want to download something but want to study in front of laptop, so during that time i want to blacken my screen. in previous version of ubuntu, i used to do this with ctrl+Alt+L, but in 14.04 it just locks the screen and scree brightness is same. please help

It didn’t work properly on my Sony vaio. Even after doing this my laptop giving me message like the system is running on low graphics mode and stopped at that point and did not start. Then I enter into single tty1 session and removed the 20-intel* file then I was able to start my laptop. So can you tell me the reason of this and give me the solution of brightness problem…

Hey Abhishek! I have another related issue. I have nvidia 840M graphics card on my machine. But when i type in “lspci| grep VGA” in the terminal, it only shows the intel card. Isn’t ubuntu recognising my nvidia card?

Hello Amar,
I had the same backlight issues with my 12.04 after updating to kernel 3.13, but creating the 20-intel.conf just did the trick. Thank you very much! (It works even better than before, because now the brightness steps are smaller so I can adjust the backlight more precisely.)

i just don’t get it … it’s not working on my asus X200CA. first i somehow get error and could enter GUI, then i repeat it and could enter the GUI but even the brightness setting couldnt move (on the power setting) but somehow every function is working. and then i update the grub, this time the brighness setting on the power setting working but still no luck with the functon key :-( please help.

It worked for me! I had problems with brightness control on Linux Mint 16 Petra running on Dell Inspiron 3537. I spent hours searching on net but none of the tricks worked including setting GRUB_CMDLINE_LINUX_DEFAULT. But This simple fix given here, that is, adding a “device” section to the 20-intel.conf file (followed by log out / log in back) worked like a breeze. Good job Abhishek!

So I followed this tutorial and it didn’t work… at first. I then followed the “featured comment” by Amar Prabhu and my brightness control DOES work now via slider however I still have to setup my shortcut keys and I’m not sure what command I need to send on the hotkeys to make it work.

This did not work for me. When I added the code mentioned above, I get a black screen and will not boot back into Ubuntu. Also, since this is a clean install when booting before this, I have never gotten a screen to allow me to select recovery mode, it normally just boots in Ubuntu from turning on the machine.

I didn’t run update-grup yet, but editing the file and rebooting seems to have fixed all of my function keys. I’m not sure why adding acpi_backlight=vendor would affect more than the backlight, but for now I’m not complaining. :)

There is a major question which no one asked you here. Let me ask you.
Your fix works partially. The fn keys are working with brightness. But after every reboot, it gets to maximum/too low on different systems. There are fixes for that as well and most used is http://askubuntu.com/questions/151651/brightness-is-reset-to-maximum-on-every-restart#151665. However, if we set the brightness to a fixed one. If we want to change the brightness again, do we need to run the steps in above link again? Or if we change the brightness using fn keys, it’ll be set as default automatically?

After I change line no 11 do I close the window? When I try and close the windows it asks to either close without saving, cancel or save as. If I do save as, what do I name it? It won’t let me replace it with the old file.

I also tried leaving the window open and doing “sudo update-grub” in the terminal, but that doesn’t seem to change anything.

Thanks, this worked perfectly! I had tried modifying the grub conf before, and that fixed the brightness but had the undesirable effect of causing the system to freeze. Your solution finally did the trick.

In my case none of the options deleted the file, when i tried with the first you put, the systems says “it can be deleted system of archives of only lecture” and the 2d option says that doesnt exist the archive or directory plz Help : /

This is great if you have intel. But I’m having the EXACT same problem with Nvidia Quadro!!! :( Can someone please tell me how to fix it so the FN brightness keys actually changes the brightness? It was only AFTER installing the proprietary Nvidia driver that this problem occured, before with the Nouveau driver I could change brightness without problems.. Also there’s an ugly Nvidia logo screen popping up for about one second during boot right before the login-screen. Can someone help, or point me in any direction please? :)

The same happened to me. To fix this, you have to boot to recovery mode. Which is, when the grub menu appears, don’t choose to boot to ubuntu, there is an another entry that should look something like “Advanced options” or “recover mode”, choose that, then a menu will appear, choose to login as root. Now you have root access to your system but all your disk is mounted in read-only mode. To remount it in a writable state, type the following command “mount -o remount,rw /” then delete the file you created, restart you system, search for another solution and when you find one, please do tell :)

Thanks for your tutorial Abhishek, it is work for login and logout, but it doesn’t work if you shutdown your computer and login to the system again. Can you give me more option how to make the brightness work permanently ? Thanks.

[…] was first noticed after I rebooted after doing a software update. The cause was an improper use of this fix I used to get the brightness control to adjust. I properly used the fix and now everything is […]

[…] Don’t worry, you are not the only who find Ubuntu too bright and you are definitely not the only one who cannot reduce the brightness in your laptop using the function keys. It’s a known bug which is ‘ported successfully’ in Ubuntu 14.04. If your video driver is Intel, you can easily fix the brightness control issue in Ubuntu. […]